feat(record): capture interactions in embedded frames

Track recording per document so injectable child frames are captured while partial frame failures remain visible in exported traces.

Co-authored-by: Cursor <cursoragent@cursor.com>

crates/bsk-cli/tests/record_stop_retry.rs

@@ -96,6 +96,7 @@ fn sample_trace() -> Trace {
             bsk: "0.1.10".into(),
             vom: VOM_FORMAT_VERSION,
         },
+        frame_capture: None,
         states: vec![TraceState {
             id: "s1".into(),
             url: "https://example.com/".into(),